Crank-case ventilating system



Gd. 29, 1929. ELLIS CRANK CASE VENTILATING SYSTEM Filed Oct. '21, 1927 ocupm za/A,

Patented Oct. 29, 1929 LOGKWOOD B. ELLIS, OF DETROIT, MICHIGAN, ASSIGNOR TO GENERAL MOTORS COR- PORATION, OF DETROIT, MICHIGAN, A CORPORATION OF DELAWARE CRANK-CASE VENTILATING SYSTEM Application filed October 211, 1927. Serial No. 227,742.

This invention relates to crankcase ventilators for internal combustion engines.

It is an object of this invention to provide a new and improved crankcase ventilating system which will eifectually remove the combustion chamber products which have escaped between the cylinder wall and piston into the crankcase. More specifically it is the object of this invention to provide a device which will remove these foul gases through the lower part of the cylinder Wall and consequently before they can enterthe crankcase proper and become mixed with the oil.

A further object is to provide a device for conducting the gases from the crankcase out through the tappet chamber and means for drawing air down from the overhead valve compartment into the tappet chamber, the

' construction here referred to being such that any particles carried by the gases from the crankcase will be practically unable to rise into the overhead valve chamber.

Other objects and advantages of the invention will appear in the course of the following description, taken in connection with the accompanying drawing, and will be particularly pointed out in the appended claims.

Fig. 1 shows a sectional view of an engine provided with my improved ventilating system, with parts broken away.

Fig. 2 shows an alternative detail of louvered cover construction.

The ventilating system in the present case is an improvement over that shown in the application of Lockwood B. Ellis, Serial No. 44761, filed July 20, 1925. That case illustrates the. ventilating system of a V-type engine while in the present case I provide a somewhat similar ventilating system for engine with upright cylinders and provided with a side tappet chamber and an overhead valve rocker arm chamber.

The drawing shows an overhead valve engine which includes a jacketed cylinder 10,

piston 12, connecting rod 14 and crankshaft 16. Mounted over the cylinder 10 is the casting 18 carrying the valve and rocker arm mechanism, and mounted on this casting is the cover 20 for the rocker arm compartment. As suggested in Fig. 2, this cover may be provided with top louvers 21 for admitting air to the rocker arm compartment; but this is not necessary in case lateral air inletopenings are provided in said cover, as shown in Fig. 1. Extending through the tubular opening 22 and down to the camshaft 24 is the tappet 26. The tappets are enclosed by the cover'28, thus forming a continuous tappet chamber 29 extending the height of the engine along one side thereof. An opening 30 is provided in the tappet chamber cover 28, and fixed in this opening and extendin downward below the dust-pan (not shown beneath the engine is the outlet tube 32. At its lower end this tube is provided with an opening 34 on the side toward the rear of the car so that the air sweeping by will produce suction on the tube. On the side of the engine opposite the outlet tube is the breather 36.

In the side of the cylinder wall is provided one or more openings 38, the inner ends of these openings intermittently establishing lateral communication between the cylinder and the tappet chamber 29, being illustrated as chambered. The exact dimensions of these openings are not material, the important feature being that the holes are open during part of the piston stroke and closed during part of the stroke.

The operation of the device will now be described. With the parts in the position shown in the drawing, the direction of movement of the air currents within the crankcase, caused bv rotation of the crankshaft, is as indicated by the arrows. Air is driven out through the openings 38 into the tappet chamber. Due to the rearward facing of the opening 34, suction is constantly exerted on the tube 32, and due to this suction the foul gases entering the tappet chamber from the crankcase are drawn out through the tube 32 and are not permitted to rise through the opening 22 into the rocker arm compartment. Suction is thus eflective at all times in the tube 32 to draw air from the rocker arm compartment through the tappet chamber into the outlet 32. This suction exerted through the tappet chamber on the overhead valve compartment is of course less in the position illustrated than when the piston is down over the openings 38. Air may enter the crankcase through the breather 36.

I have found the arrangement described sufiicient to keep a current of air from the rocker arm compartment into the tappet chamber. However, if desired, one or more tubes 42 may be used, extending from lateral air inlet openings in the cover of the rocker arm compartment into the crankcase. Whether or not the tube 42 is used, the top louvers 21 suggested in Fig. 2 may be omitted from the rocker arm cover 20, the lateral openings thereto being sufficient. As the tube 42 connects with the crankcase on the side on which the connecting-rod moves upward, a current of air may be kept moving through the tube 42 into the rocker arm compartment, the length, the substantial verticality, and the point of connection of said tube being unfavorable to any rise of solid particles therethrough. This current continues down through the opening 22 and prevents entry of the gases from the tappet chamber into the rocker arm compartment.

What I claim is:

1. In an internal combustion engine having a crank case and including aside chamber and an overhead chamber connected therewith, an outlet leading from said side chamber, means terminating outside of said engine for maintaining suction through said outlet, an opening from the crankcase through a lateral wall of said side chamber, and an inlet opening in said crankcase.

2. In an internal combustion motor having a crank case and a cylinder and including a side chamber and an overhead chamber connected therewith, an air inlet opening in said overhead chamber, an outlet leading from said side chamber, means for maintaining suction through said outlet, an intermittently cover opemn leading from the cylinder into the side c amber, and an air inlet opening in the crankcase.

3. In an internal combustion motor having a crank case and including a side chamber and-an overhead chamber connected therewith, an air inlet opening in said overhead chamber, an air inlet opening in said crankcase, an opening from the crankcase into the side chamber, an outlet leading from said side chamber, and means for causing a curin said crankcase, an intermittently covered rent to flow from said crankcase and overhead chamber into said side chamber and out said outlet. 7

4. In an internal combustion motor having a crank case and a cylinder and including a side chamber and an overhead chamber connected therewith, an air inlet opening in said overhead chamber,'an air inlet opening leading from the cylinder into the side chamber, and means for causing a current to flow from said crankcase and over- 6. In an internal combustion motor having a crank case and a cylinder and including a side chamber and an overhead chamber connected therewith,) an air inlet opening in said overhead cham er, an air inlet opening in said crankcase, an intermittently covered opening leading from the cylinder into the side chamber, and a suction tube connected to said side chamber.

7 In an internal combustion motor having a crank case and including a side chamber and an overhead chamber connected therewith, a conduit connecting said overhead chamber with said crankcase, an air inlet opening in said crankcase, an opening from the crankcase into the side chamber, and a suction tube connected to said side chamber.

8. In an internal combustion motor hav ing a crank case and a cylinder and including a side chamber and an overhead chamber connected therewith, a conduit connecting said overhead chamber with said crankcase, an'air inlet openin in said crankcase, an intermittently covere opening in the cylinder leading into said side chamber, and a ilzction tube connected with said side cham- 9. In an internal combustion motor having a crank case and includin a side chamber and an overhead cham er connected therewith, an opening in said overhead ch a1 aber, an inlet opening in the crankcase on the side where the connecting rod moves downward, an opening leadin from said crankcase into said side cham er, and a suction tube connected to said side chamber.

10. In an internal combustion motor having a crank case and a cylinder and including a side chamber and an overhead chamber connected therewith, an opening in said overhead chamber, an inlet opening'in the crankcase on the side where the connecting rod moves downward, an intermittently covered opening in the cylinder, said opening leading into said side chamber, and a suc head chamber, an intermittently covered opening in the cylinder, said opening leading from the crank case into the side chamher, and a suction tube connected to said side chamber.

In testimony whereof I afix my signature.

LOOKWOOD B; ELLIS. 

